Low profile pump motor lead protector

ABSTRACT

A low profile pump motor lead protector with a head guard and a trailing guard, the head guard including a front section with a front end and a rear section with a rear end, the trailing guard having a pin end for insertion in a head guard socket, the lead protector for protecting a motor lead of a pump and motor assembly of a downhole production string for surfacing fluid from a reservoir such as a subterranean oil well.

PRIORITY CLAIM AND INCORPORATION BY REFERENCE

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 16/416,578 filed May 20, 2019 which is acontinuation of U.S. Non-Provisional patent application Ser. No.15/651,704 filed Jul. 17, 2017 now U.S. Pat. No. 10,323,643 which is acontinuation of U.S. Non-Provisional patent application Ser. No.15/165,078 filed May 26, 2016 now U.S. Pat. No. 9,742,241 which is acontinuation of U.S. Non-Provisional patent application Ser. No.14/266,994 filed May 1, 2014 titled LOW PROFILE PUMP MOTOR LEADPROTECTOR now U.S. Pat. No. 9,356,484 and claims priority to U.S.Provisional Patent Application No. 61/883,347 filed Sep. 27, 2013 titledPUMP MOTOR LEAD PROTECTOR which is incorporated herein, by reference, inits entirety and for all purposes. U.S. Pat. No. 6,863,124 B2 filed Dec.17, 2002 is incorporated herein, by reference, in its entirety and forall purposes.

BACKGROUND OF THE INVENTION Field Of The Invention

The present invention relates to the mechanical arts. In particular, theinvention relates to a manufacture incorporating structural parts forcovering and protecting electrical leads connected to a pump motor in adownhole pumping apparatus.

Discussion Of The Related Art

Electric motor driven pumps may be used in severe service locations suchas those at depth in downhole oilfield applications. For example, suchan apparatus may be used to return oil to the surface. Electrical andother leads that attach to the pump and its motor typically follow astring of pipe from the downhole location to a “topside” location at ornear the earth's surface. Means to protect these leads from damageduring installation, use and recovery of the pump have advanced littleduring recent years, perhaps due to the industry's reluctance to rely onnew and arguably unproven equipment.

SUMMARY OF THE INVENTION

The present invention discloses a low profile pump motor lead protector.In various embodiments, the protector covers leads from a pump motorsuch as leads for one or more of electric power, electric telemetry,optical telemetry, fluid, pressurized fluid, and other similarly usefulleads.

In an embodiment, a lead protector is for use with a downhole pump andmotor in an oil production string comprising: a head guard and atrailing guard; the head guard covering a head end of a lead; thetrailing guard covering a portion of the lead trailing from the leadhead end; and, the head guard and the trailing guard configured tosubstantially cover the lead as it passes through a space between aproduction string casing and the pump and motor.

In various embodiments, the protector includes a head portion and atrailing portion either or both of which may be made of one or severalparts. For example, some embodiments utilize one part head portion and amultipart trailing portion.

In various embodiments, a head guard and a trailing guard provide ameans for continuously protecting a lead such as an electric power,electric signal, or other lead from the pump and motor. In anembodiment, the protector is configured to guard at least an electricpower lead from a pump motor used downhole in an oil production string.

In various embodiments, the lead protector is mounted to a pump andmotor apparatus. The head guard covers a penetration/terminal of thepump and motor apparatus where electric and/or other leads to beprotected exit the pump and motor apparatus. In various embodiments, thehead guard is made from metal such as stainless steel and has aclam-shell like construction providing a void on its bottom side toreceive the abovementioned lead(s). And, in various embodiments, thehead guard is configured to mate with the trailing guard to provideprotection of a continuous or substantially continuous length of thelead(s).

And, in various embodiments, the trailing guard has a channel like shapewith opposed sides and a web therebetween. And, in various embodiments,the trailing guard is made from a metal such as stainless steel. Someembodiments of the protector utilize several mated trailing guards suchas overlapping trailing guards.

In an example, the pump and motor apparatus is surrounded by a casingsuch that a small annular like clearance is formed between the pump andmotor apparatus and the surrounding casing. Here, the protector shieldsthe lead(s) against physical damage that might result from the lead(s)touching the casing or other objects within the annulus.

With various embodiments of the pump and motor apparatus and insertionof the pump and motor apparatus in particular wells or well casings,there are particular dimensions such that different production stringshave different dimensions which call for appropriate pump and motorapparatus to accommodate physical dimensions and quantities ofproduct/oil to be produced.

In an exemplary operation, the lead protector provides a lead coveraffixed to a pump and motor apparatus via a band like clamping system.During insertion of the pump and motor apparatus in a surrounding suchas a casing, during operation of the pump and motor apparatus, andduring extraction of the pump and motor apparatus from a surroundingsuch as a casing, the lead protector shields the covered lead(s) fromdamage such as damage caused by rubbing, pulling, scraping, and thelike. Embodiments of the invention provide a lead protector of a lengththat protects from damage occurring in the annulus between a casing andthe pump and motor apparatus.

In an embodiment, a method of using a low profile lead protector toprevent damage to an electrical lead of a pump motor during insertion,operation, and removal of an electric submersible pump assembly in anoil well casing comprising: providing a head guard including a frontsection with a front end and a rear section with a rear end, the headguard front section tapering toward the head guard front end anddefining a ventral curved surface for mating with a pump motor exteriorand defining a dorsal surface in the shape of a truncated triangle, andincluding bolt holes in opposite corners of and passing through theventral curved surface; providing a head guard rear section that isdepressed with respect to the front guard section, the head guard rearsection defining a ventral curved surface for mating with a pump motorexterior and including a socket flanked by flanges with bolt holes;providing a trailing guard having an “n” shaped cross-section with sixsides, two of the six sides being opposed and having aligned slots, thetrailing guard secured at one end by the head guard rear section; on aproduction string, placing the trailing guard over a section of the pumpmotor lead and placing the head guard over the pump motor lead where itjoins the motor and over an end portion of the trailing guard; on theproduction string, bolting the head guard to the pump motor; on theproduction string, banding the trailing guard to the pump and motorassembly; during insertion of the production string, the lead protectormoving relative to the casing and the lead protector and fending offstationery obstructions to protect the pump motor lead; during operationof the production string, the lead protector shielding the pump motorlead from contact with the casing and objects in an annulus between thecasing and the pump motor to protect the pump motor lead; and, duringextraction of the production string, the lead protector moving relativeto the casing and the lead protector and fending off stationeryobstructions to protect the pump motor lead.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described with reference to the accompanyingfigures. In the figures, like reference numbers indicate identical orfunctionally similar elements. The accompanying figures, which areincorporated herein and form part of the specification, illustrate thepresent invention and, together with the description, further serve toexplain the principles of the invention and to enable a person skilledin the relevant art to make and use the invention.

FIGS. 1-3 show a motor lead protector in accordance with the presentinvention.

FIG. 4 shows an embodiment of a head guard that is a part of the motorlead protector of FIG. 1.

FIGS. 5-7 show an embodiment of a trailing guard that is a part of themotor lead protector of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The disclosure provided in the following pages describes examples ofsome embodiments of the invention. The designs, figures, and descriptionare non-limiting examples of embodiments they disclose. For example,other embodiments of the disclosed device and/or method may or may notinclude the features described herein. Moreover, disclosed advantagesand benefits may apply to only certain embodiments of the invention andshould not be used to limit the disclosed invention.

Unless otherwise indicated, parts that are connected or coupled may bedirectly or indirectly connected and may have other devices interposedtherebetween including devices known to persons of ordinary skill in theart.

FIGS. 1-3 show views of a pump motor lead protector in accordance withthe present invention 100, 200, 300. A pump motor lead is omitted fromFIGS. 1, 3 for clarity and is shown in FIG. 2 (See e.g., 202).

FIG. 1 shows a pump motor lead protector 200 mounted alongside a pump104 and motor 102 assembly 103 that may be suspended from productiontubing 110 for producing product from a reservoir, such as asubterranean oil well and/or reservoir 113 to a receiving facility 115,such as a production shut-off valve. Flow arrows showing inlet flow fromthe reservoir and pump outlet flow 112 indicate typical production ofliquids such as oil or crude oil. In various embodiments, the pump andmotor assembly is an electric submersible pump and motor assembly.

Applications include production facilities with an outer casing such ascasing 108 into which the pump 104 and motor 102 are inserted. Asskilled artisans will recognize, the pump and motor assembly may also beused in a hole or well-bore that has no casing. And, as skilled artisanswill recognize, the pump may be above the motor as shown, or the pumpmay be below the motor when designed for such use. An upper end of thepump 166 may, in various embodiments, be coupled with a string ofproduction tubing 110.

When the pump and motor are moved in a confined space like the casing108, the motor lead protector 200 assists in protecting the motor lead202. For example, the motor lead protector covers the motor lead (SeeFIG. 2) such that it is not rubbed against or snagged by adjacent and/orfixed structures such as the casing inside side wall 124 during pump 104and motor 102 insertion into or removal from the casing.

A head guard of the motor lead protector 210 covers the motor lead 202where it passes through a motor sidewall 122. Some embodiments of thehead guard include a head guard front or head guard front section 212with a forward sloped or wedge-like nose 205 that guides pump 104 andmotor 102 when moved in the casing. Locating the motor lead protectorand in particular the head guard front section between the motor and theinside side wall of the casing 124 spaces the motor apart from thecasing 121.

In various embodiments, connection of the pump motor lead protector 200with the motor 102, pump 104, and production tubing 110 is by fastenersand/or other restraints. For example, bolts may be used to affix thehead guard 210 to the motor and straps or bands 106 may be used to affixthe trailing guard 220 to the motor, pump and/or production tubing. Asskilled artisans will recognize, embodiments provide a motor leadprotector that extends at least from a motor lead entryway 120, and inthe direction of the receiving facility 115.

FIG. 2 shows an enlarged side view of the motor lead protector ofFIG. 1. Among other things, this view shows a motor lead 202 that iscovered by the motor lead protector. And, FIG. 3 shows an enlarged topview of the motor lead protector of FIG. 1.

The motor lead protector 200 includes the head guard 210 and thetrailing guard 220. The head guard includes a head guard front section212 and a head guard rear section 214. Like the trailing guard 220, thehead guard 210 provides motor lead 202 protection. For example, ahollowed out head guard provides a protected space for a motor lead 202which has an exemplary motor lead head end 203. Here, the motor leadhead end is shown entering the motor lead entryway 120 through the motorentryway sidewall 122.

In some embodiments, the motor lead 202 connects with a lead terminationblock 160 such as an electrical terminal block or receptacle that isaccessible on the motor exterior. And in some embodiments, a motor leadplug 162 interconnects with a mating lead termination block, for examplea bayonet plug and socket or another suitable arrangement may be used.The terminal block may extend from a sunken motor surface portionproviding a low profile motor terminal block. In various ones of theseembodiments, the motor lead need not pass through a motor lead entryway,a feature that may enable better sealing of the motor internals againstcontaminants outside the motor.

In various embodiments, head guard 210 features include the head guardfront 212 section with a hollowed out interior 240 for receiving a motorlead 202, and motor fastener means such as peripheral bolt holes 205. Insome embodiments bolts passing through front guard peripheral bolt holesare anchored in matched threaded holes of the motor. For example, boltholes in a motor used to mount a traditional motor lead entryway covermight be reused when the front guard replaces the traditional coverduring pump motor lead protector installation.

And, in various embodiments, head guard features include a head guardrear section 214 with a box 218 extending from the front section andperipheral or flanged fastening means 216 to either side of the box. Thebox may be in the form of a closed box or a box with an open side(s). Insome embodiments, the box is a rectangle with an open side or sideportion adapted to receive the cross-sectional shape of a mating end(See e.g. 410) of the trailing guard 220. And, in some embodiments thebox is adapted to fit and/or fittingly receive the cross-sectional shapeof a mating end of the trailing guard as where the box and the matingend have equal numbers of sides. Fastener means such as bolt holes 213may be used with peripheral or flanged fastening means.

FIG. 3 shows, inter alia, a dorsal top side 219 of the head guard 210.Dimensions include an overall length “a1” and a width such as a maximumwidth of “a2.” FIG. 2 shows, inter alia, a side view of the head guardwith a head guard front section 212 height of “a3” which is less than ahead guard rear section 214 height of “a4”. In various embodiments, ahead guard major aspect ratio is (a1/a2) with values greater than two.And, in various embodiments, the head guard rear section with height a4is depressed with respect to the adjacent head guard front section withheight a3.

And, in some embodiments a head guard minor aspect ratio is (a1/a3) withvalues greater than four. In these embodiments, the lead protector headguard may be described as a “low profile” lead protector.

FIG. 4 shows an enlarged perspective view 400 of an embodiment of thehead guard of FIG. 2. As seen, the head guard 210 is ready for matingwith an adjacent trailing guard portion 220. In an embodiment, a headguard box 218 includes a box mouth 211 that is for receiving a free end410 of the trailing guard assembly. Skilled artisans will appreciatethis “pin and socket” joint arrangement might be reversed in someembodiments.

Also shown is a head guard 210 end 404 revealing a curved interior orcurved ventral surface portion 402 of the head guard. Curved with aradius “R,” the head guard may be designed to snugly interface with asimilarly curved motor 102 exterior surface 150. Other portions of thehead guard such as the head guard rear section 214 may be similarlyshaped for similar reasons.

The embodiment shown has a head guard front 212 with a wedge-likeforward slope along its longitudinal axis (e.g., t1<t2). In someembodiments, the head guard front section has a raised exterior rib 406that extends about parallel to a head guard longitudinal axis. And, inan embodiment, a dorsal rib such as a bumper rib or a central bumper ribthat extends along at least a portion of the head guard and in adirection that is somewhat parallel to the head guard longitudinal axis.

As skilled artisans will appreciate, head guards with a wedge-likeforward slope provide means to reduce the leading cross-sectional area420 and thickness t2, attributes lowering the risk of frontal impactswith fixed structures that may tend to move the head guard relative tothe motor 102. Where the rib is included, otherwise deleterious effectsof side impacts and friction with the head guard and the casing insidesidewall 124 may be further reduced.

Turning now to consider the trailing guard 220, the head guard 210 isfor assembly with the trailing guard 220. Some head guard embodimentsprovide for a box-like connection wherein a trailing guard 220 is matedwith and/or inserted in a box mouth 211 of a head guard box 218.

In various embodiments, the trailing guard is in the form of a tube,partial tube, or channel-like structure 220 and corresponding slots 230in opposite sidewalls of the trailing guard provide a means forstrapping or banding 106 the trailing guard to secure it against one ormore of the pump, motor, and production tubing (See also FIG. 1). In anembodiment, bands secure the trailing guard to at least one of the pump104 and the motor 102. And, in an embodiment, bands secure the trailingguard to the pump and the motor. And, in an embodiment bands securingthe trailing guard include bands that encircle the production tubing110.

FIGS. 5-7 show an embodiment 500, 600, 700 of the trailing guard 220 ofFIG. 2.

In various embodiments, including the embodiment of FIG. 5, the channelmay be described as having multiple sides, for example 7 sides, one ofwhich 502 is open. Here, a channel ridgeline 510 is the juncture offirst sidewalls 512, 522 forming a somewhat flattened “A” frame likestructure. Adjoining respective legs of the “A” as first leg extensionsare second sidewalls 514, 524 forming an obtuse angle with respectivefirst sidewalls. Adjoining these first leg extensions are second legextensions/third sidewalls 516, 526 forming near right angles withrespective first sidewalls.

Some trailing guard cross-sections may be referred to as “n” shapedcross-sections, more particularly as four or more adjoining panelsforming an “n” shaped cross-section and yet more particularly as 6adjoining panels forming an “n” shaped cross-section.

FIG. 6 shows the channel 220 cross-section of FIG. 5. A channel overallheight “h” and a channel overall width “w” are shown along with achannel interior 602. The channel open side 502 faces an adjacentstructure 604 such as the motor 102, pump 104, or production tubing 110.

In various embodiments a strap or band 106 and a motor lead 202 passthrough the channel interior via corresponding channel slots 230 withexemplary major “s2” and minor “t2” slot dimensions selected toaccommodate the band. Here, a motor lead 202 is located beneath the bandsuch that a protective clearance “c” exists between the strap or bandand the motor lead. A benefit of the protective clearance is relievingthe motor lead as a strap or band bearing point and using the channelinstead to transmit forces to the structure via its two leg extensions516, 526 without bearing on the motor lead. Yet another benefit of theprotective clearance is the avoidance/mitigation of strap or band tomotor lead chafing.

FIG. 7 shows mating ends 702, 704 of respective trailing guards depictedas channel sections 220, 720. As shown here, the pin like end 704 of onetrailing guard 720 is for insertion into the socket-like end 702 ofanother trailing guard 220. As skilled artisans will appreciate,trailing guard mating ends may be configured as needed to accommodatevarying trailing guard cross sections. And, as skilled artisans willappreciate, trailing guard sections with mating ends provide a means ofadapting trailing guard length to accommodate varying applications.

Materials of construction for the head guard 210 include metals anddense plastics. For example, a metal such as stainless steel and aplastic such as polyether ethyl ketone (“PEEK”), known for its toughnessand low coefficient of friction, might be used according to theapplication. As indicated by the choice of application, materials, cost,schedule, and availability, head guards may be machined, cast, orproduced by other suitable methods such as powder metallurgy orsintering. In an embodiment, the head guard is made from stainlesssteel.

Materials of construction for the trailing guard 220 include metals anddense plastics. For example, a metal such as stainless steel and aplastics such as polycarbonate and polypropylene might be used accordingto the application. As indicated by the choice of application,materials, cost, schedule, and availability, trailing guards may bemachined, cast, extruded, rolled, or produced by other suitable methodssuch as powder metallurgy or sintering. In an embodiment, the trailingguard is made from stainless steel.

In operation, embodiments of the lead protector provide a lead coveraffixed to a pump and motor assembly, for example via a band likeclamping system. For example, protection is provided during insertion ofthe pump and motor apparatus in a surrounding such as a casing, duringoperation of the pump and motor apparatus, and during extraction of thepump and motor apparatus from a surrounding such as a casing. The leadprotector shields the covered lead(s) from damage such as damage causedby rubbing, pulling, scraping, and the like. Among other things,embodiments of the invention provide a lead protector of a length thatprotects the motor lead from damage occurring in the annulus between acasing and the pump and motor apparatus.

Example: In an oil well application with a well casing, the pump motorlead protector was installed on a 3.75 inch outside diameter pump andmotor assembly. The head guard was dimensioned to fit within the annulusbetween the motor and the casing inside wall. As described above, awedge-like front guard and a mating trailing guard with slottedsidewalls was installed via metal bands passing through the slots andaround the pump and motor assembly. Bolts passing through front guardperipheral bolt holes and anchored in matched threaded holes of themotor secured the head guard to the motor. Channel cross-section,channel slot locations, and motor lead dimensions provided a protectiveclearance between the motor lead and banding passing through the channelinterior. The assembly was inserted in the casing and lowered 1100 feetinto the reservoir for fluid production. During lowering, the assemblynavigated the route through the casing, including casing bend radii onthe order of 3 to 4 degrees. In operation, the pump and motor surfacedfluid normally. This evidence shows the pump motor lead protectorprevented debilitating rubbing and snagging damage to the motor lead andfurther that the protective clearance prevented debilitating rubbing,chafing, and compression damage between the band and the motor lead.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation. It will be understood by those skilledin the art that various changes in form and details can be made thereinwithout departing from the spirit and scope of the invention. Thus, thebreadth and scope of the present invention should not be limited by anyof the above-described exemplary embodiments, but should be defined onlyin accordance with the following claims and their equivalents.

What is claimed is:
 1. A method of protecting a pump motor leadcomprising the steps of: mounting a pump motor lead protector alongsidea pump and motor assembly for installation in a production string thatwill be inserted in a wellbore; covering the pump motor lead with thepump motor lead protector including a shoe-shaped head guard and achannel-shaped trailing guard; covering the pump motor lead where itextends from the motor with the head guard, the trailing guard insertedin the head guard; covering the pump motor lead where it extends fromthe head guard with the trailing guard; holding the head guard to themotor with a plurality of bolts; holding the trailing guard against atleast one of the pump, motor, and production tubing with an encirclingband; and, during lowering of the production string into the wellbore,the pump motor lead protector preventing rubbing of the pump motor leadagainst adjacent stationary surfaces.
 2. The method of claim 1 furthercomprising the step of inserting the band through passages in opposedsides of the channel.
 3. The method of claim 2 further comprising thestep of locating the pump motor lead between the band and an open sideof the channel.
 4. The method of claim 3 wherein a clearance between theband and one of the pump, motor, and production tubing is larger than apump motor lead dimension such that the band does not squeeze the pumpmotor lead.
 5. The method of claim 3 wherein a clearance between theband and one of the pump, motor, and production tubing is for preventingdamage to the pump motor lead.
 6. The method of claim 5 furthercomprising holding the head guard to the motor with at least four bolts.7. The method of claim 5 further comprising thinning of the head guardat locations where bolts pass through the head guard.
 8. The method ofclaim 5 further comprising forming an open socket in the head guard forreceiving the trailing guard.
 9. The method of claim 5 furthercomprising a thinning of the head guard thickness when moving toward ahead guard leading cross-sectional area.
 10. The method of claim 5wherein the head guard front section includes a wedge-shaped forwardslope.